Add Monaco Editor Tree View for Document Navigation

[andre-dietrich]

Add a tree view panel to the Monaco editor that shows the document structure and enables quick navigation.

Features:

• Adds a collapsible tree view panel showing document structure based on headings
• Integrates with Monaco editor's internal tree view API for native look and feel
• Provides quick navigation through document sections
• Toggle via Ctrl+B/Cmd+B keyboard shortcut
• Auto-updates as the document changes

Implementation Details:

• Create TreeViewProvider class to handle Monaco's internal tree view
• Add tree view container next to editor
• Parse markdown headers for document structure
• Add toggle functionality and keyboard shortcuts
• Ensure proper cleanup on component destruction

Files to Create/Modify:

1. src/ts/TreeViewProvider.ts - New file for tree view implementation
2. src/components/Editor.vue - Modify to add tree view support

Testing:

• Test tree view initialization
• Verify navigation functionality
• Check auto-update with document changes
• Verify proper cleanup on component destruction
• Test across different Monaco editor versions

Design:

• Tree view panel on left side of editor
• Collapsible/expandable sections
• Visual hierarchy for different heading levels
• Consistent with Monaco editor's theme